This invention generally relates to structural materials of the type suitable for building purposes and specifically to composite panel materials that include a metal skeleton structure.
Metal skeleton type panel materials are known in the art of vehicle and aircraft construction and attempts have been made to use such panels for building purposes. For example, the panels disclosed in Belgian Pat. No. 565,212 (J. Couelle) are intended as load-bearing walls for building purposes and consist of a metal skeleton of two metal plates spaced apart in parallel planes, each plate comprising a plurality of elements that extend into the space between the two plates and are intended to stiffen the skeleton structure. One or both of the external surfaces of these prior art panels can be provided with coatings of a porous solid material, such as gypsum or concrete, and each plate is equipped with a large number of tongues formed, for example, by punching-out and bendingly deforming portions of the plates. At least some of these tongues extend into the space between the plates but may also project from the outside of the skeleton to improve adhesion of the porous coating of the skeleton. Bracing or stiffening of the skeleton is achieved by interconnecting the ends of the tongue-shaped elements projecting from both plates by electrical welding.
Skeleton-type panels for vehicles or aircrafts are disclosed in French Pat. No. 1,045,315 and are made of two parallel metal plates. Bracing elements are provided between the plates and these elements can be formed as separate elements or on either or both plates, and are connected to the other plate, or to both plates, by electrical welding or by means of an adhesive.
Aside from the problems of connecting the bracing elements with each other or with the plates, such prior art panels do not provide for a sufficient load-bearing capacity, i. e. the mechanical strength of a vertically arranged panel under the impact of a load applied vertically at the top surface of the panel, if sheet metal plates of commercially feasible -- i. e. as viewed from the cost of materials in the building industries -- qualities and gauges of the metal plates as well as commercially acceptable manufacturing methods are to be used. This is due to the fact that the load-bearing capacity of prior art panels is substantially limited by the load-bearing capacity of conventional metal skeletons, i. E. their lack of resistance against buckling, when used as load-supporting walls. Furthermore, joining of the bracing elements with each other or with an adjacent plate tends to present substantial problems of manufacture.